Carpal tunnel syndrome 85456589658985888

Carpal tunnel and syndrome

1. Carpal tunnel syndrome Dr Srinath S R Professor and Unit Head Department of Orthopaedics

2. Content Carpal tunnel syndrome Introduction Anatomy Etiopathology Clinical features and signs Management

3. Introduction The original description of median nerve compressive neuropathy was reported by Sir James Paget in 1854. Moersch was the first to coin the term "carpal tunnel syndrome" (CTS)'

4. Anatomy The deep carpal arch forms a concave surface, which is converted into a tunnel by the overlying flexor retinaculum (transverse carpal ligament).

5. Boundaries Roof: transverse carpal ligament Floor: central carpal bones Medial wall: pisiform and hamate Lateral wall: trapezium and scaphoid

6. Contents of carpal tunnel The carpal tunnel contains A total of 9 tendons (flexor pollicis longus, Four tendons of flexor digitorum profundus , Four tendons of flexor digitorum superficialis) surrounded by synovial sheaths, and the median nerve. The palmar cutaneous branch of the median nerve is given off prior to the carpal tunnel, travelling superficially to the flexor retinaculum.

7. The dimensions of the carpal tunnel The width at the narrowest area corresponding to the level of the hook of the hamate-is 20 mm, at the distal end is 26 mm, and at the proximal end is 25 mm. The depth is 10 mm at the narrowest point and about 13 mm at the deepest point, Roughly having an hour-glass shape.

8. At the distal end of the TCL, the median nerve divides into recurrent motor branch to the thenar muscles to the sensory branches of the thumb, index, middle, and the radial half of the ring finger

9. Lanz classified the recurrent motor branch into the following four types based on its relationship with the TCL Extraligamentous Subligamentous Transligamentous Supraligamentous Lanz classification

10. Transligamentous (23%) Extraligamentous thenar branch (46%) Subligamentous(31%) Supraligamentous

11. Etiopatology The primary pathophysiology causing CTS is an increase in the interstitial pressure in the carpal tunnel. The normal interstitial pressure within the carpal tunnel is about 2.5 mm Hg. This can reach above 30 mm or more in maximal wrist flexion and extension even in normal hands. Pressures above 30 mm Hg have been found to result in nerve dysfunction. By far, idiopathic etiology is most common and associated with up to 80% cases .

12. Incidence: affects 0.1-10% of general population Up to 70% of patients have bilateral carpal tunnel syndrome Demographics Age: manifests in adults aged 40-60 years old uncommon in children Sex: female:male 3:1 ratio 

13. Clinical Features The classical symptoms of CTS are Paraesthesia Burning sensation Pain along the median nerve distribution, which is the lateral three and a half fingers and the thumb. The onset is usually insidious, spontaneous, and nocturnal. In some patients, the syndrome follows trauma (e.g., after a displaced Colles' fracture) or it may be associated with disease of the wrist joint.

14. The palm is typically spared as it is supplied by the palmar cutaneous branch of the median nerve given off proximal to the tunnel. The symptoms may at times be localized to one or two digits also. The symptoms are mostly nocturnal, waking the patient from sleep, and she/he then has to shake the hand vigorously to be rid of the symptoms. Some patients also complain of an upward radiation of the symptoms even up to the shoulders. In the daytime, symptoms are triggered by activities that keep the wrist flexed for a prolonged period of time. As the condition progresses, features of thenar muscle weakness commence.

15. The patient complains of easy fatigability on repetitive use of the hand and an inability to abduct and oppose the thumb at later stages. With further reduction of sensation, there is difficulty in identifying objects by stereognosis as well as in doing activities of daily living (ADL) such as hooking a blouse or putting the buttons of the shirt.

16. Signs Various provocative maneuvers are described which will help in the diagnosis of CTS. It is advised to conduct the sensory evaluation in the patient before provocative maneuvers, as provocative tests may alter the sensory perception of the patient. Vibration sense and two-point discrimination (2PD) are routinely used in evaluation. Reduction in sensory perception in the median nerve area is the basic hallmark of all these tests for the diagnosis.

17. Phalen test (wrist flexion) The patient is standing or sitting. The patient is asked to push the back of the hands (dorsal surface of the hands) together and hold this position for 30-60 seconds. Positive when the patient's symptoms are reproduced: paresthesia (burning, tingling, numbness) along median nerve distribution .

18. Reverse Phalen's test( wrist extension) The patient is standing or sitting. The patient is asked to push the palms together and hold this position for 30-60 seconds. Positive when the patient's symptoms are reproduced: paresthesia (burning, tingling, numbness) along median nerve distribution.

19. Tinnel sign Examiner percusses over the median nerve at the wrist lightly Tingling/shock-like sensation along the median nerve distribution.

20. Drukan test( carpal compression test ): Examiner presses the carpal tunnel with his thumb for 30 seconds Tingling and numbness in the median nerve distribution Gilliat test( Torniquet test) Tourniquet is inflated around the arm to the systolic pressure for 60 seconds Tingling and numbness in the median nerve distribution

21. A self-administered hand diagram – Katz hand

22. CTS-6 Evaluation Tool: a validated clinical tool for diagnosis of CTS.  A score >12 is indicative of 80% probability of CTS. A score of >5 is indicative of 25% probability.   

23. Imaging Radiographs not necessary for diagnosis and not routinely indicated MRI or CT scan Indications Consider for space-occupying lesion. rarely indicated Ultrasound   increased cross-sectional area (CSA) of the median nerve >10mm² at the level of the pisiform/proximal edge of transverse carpal ligament is associated with CTS 

24. Xrays /radiographs They reflect a bony cause such as a lunate lying within the carpal tunnel following a perilunate injury or malunited distal radius fractures which alter the shape of the carpal tunnel. A carpal tunnel view is taken with the palm placed on the cassette and the wrist hyperextended by the patient. The X-ray beam is angled along the volar aspect of the carpal tunnel to a point 2.5 cm distal to the base of the fourth metacarpal at an angle of 25°-30° to the long axis

25. CT scan delineate the fractures of carpal bones lying within the carpal tunnel

26. USG AND MRI An increase in the cross-sectional area (CSA) of the median nerve in the carpal tunnel and a ratio of CSA of median nerve at the level of pisiform and distal radius (swelling ratio) are used. The CSA, at the inlet of carpal tunnel, cutoff value for diagnosis of CTS is reported as 10.7 mm² with a sensitivity and specificity nearing 63%. Similarly , palmar bowing of the flexor retinaculum in the grasp position measured at the level of the hook of the hamate is also used as a diagnostic measurement.

27. USG

28. MRI

29. Electro-diagnostic studies(NCS/EMG). The gold standard for diagnosis. The criteria for diagnosis of CTS are two or more of the following: Prolonged conduction velocity of the median nerve across the wrist, increased duration of action potential, a polyphasic contour. The median nerve is stimulated just proximal to the wrist, and the beginning of muscle action potential in the abductor pollicis brevis is noted.

30. Diagnosis can be made purely based on history and physical examination and can be confirmed with EMG/NCS and ultrasound

31. Treatment The management of CTS may be nonoperative or operative. Etiological factors responsible for compression must be looked for and corrected first. Bony deformity, neoplasm, or other diseases such as inflammatory tenosynovitis requires surgical treatment such as corrective osteotomies or a synovectomy. When no local cause for compression can be established, and the symptoms are subjective and mild-to-moderate, conservative treatment such as splinting and corticosteroid injection can be tried

32. When symptoms are continuous or when objective signs such as sensory loss and motor wasting are seen, surgical decompression is indicated.

33. Non-Operative Splinting A carpal tunnel splint may be used, especially at night, to alleviate symptoms.

34. NSAIDs and Other Measures Early treatment with NSAIDs, diuretics, B6 supplements, and pregabalin has been said to provide symptomatic relief in some patients. Similarly, nerve gliding exercises and hatha yoga have been found to be beneficial in mild stages. Avoidance of repetitive stress and ergonomic factors contributing to CTS maybe beneficial.

35. Surgical treatment The mainstay in the treatment is surgical decompression of a tight flexor retinaculum Open carpal tunnel release Endoscopic carpal tunnel release

36. Open carpal tunnel release A longitudinal incision 1-1.5 inch long over the transverse carpal ligament just distal to the distal wrist crease and ulnar to the palmaris longus tendon axis extending up to a line drawn along the abducted thumb. The skin is incised to expose the fine transverse fibers of the flexor retinaculum. The palmar cutaneous nerve should be protected, if encountered. A sharp #15 knife is used to make a cut in the retinaculum, exposing the median nerve protected by its filmy covering fascia.

37. Thank you